What Do You Hear When You Adjust VTA?

I agree, again.
One thing that has helped me a lot is to play many records within a boxed set. Then you can be pretty sure the pressings are more or less uniform in vinyl thickness and the cutting angle. One set I have has aprox 100 records in it of all different periods in classical music. You get harpsichord - very difficult if the VTA is too high - strings, organ music -plodding, poor muffled bass if VTA to low, voice (opera) which sounds a mess if VTA either way is incorrect.
Pretty quickly you can dial it in.

There is no general rule for the VTA (and the results), probably some explanation will be useful:
1. All up and down (VTA) is depending of the angle the grooves were cut into the record.... different years, different angles, different labels, no Standard...
2. The diamonds from the cartridges have also some influence (Shibata, Paroc....), but even more important the polishing of the diamond (contact area). When the angle is "right" into the groove, you simply habe an optimized contact area and you will hear more details, specially in the higher frequencies.

No matter what Arm or cartridge you use, it depends on your own findings.
Let#s talk about an original from the 60's, done with a few microphones...normally the Arm has to be a bit lower in the rear, when you do that, the sonic result is like "zooming into the Soundstage", it gets wider and you are more "in it". When done wrong it is like listening to a "point source" between your speakers.

For stylus that elliptical or non-fine lined, the VTA is less critical. Generally the description of tighter non-muddy bass and clean highs makes sense.

But for a fin-line or Shibata stylus I think you need to listen a bit differently. The groove wall modulations for bass are large, and any semi-aligned crtridge will play them. But high frequencies are very small, to the point where the angle of the cutting head plays a major role. Since a fine line stylus shape is also narrow it becomes apparent that the high frequency grooves must align with the narrow stylus edges.

Therefore you need to listen to leading edge transients on cymbals and bells and such. If you get that right then all else should fall into place.

Do a search for SRA. The Stylus Rake Angle (SRA) is not exactly the same as the Verticle Tracking Angle (VTA)and much has been discussed on this subject. In the SRA search under the analog section there is a discussion about using a USB microscope for setting the SRA. About half way down Doug Deacon has an entry that I found enlightening and specifically discusses the audible changs to listen for as you adjust the SRA up or down. Doug adusts his by ear on each album and has keen insight to what you can listen for. Very interesting read that helped me find the proper SRA for my table/arm/cartridge by listenind also. I would place a link to it, but I do not know the proper procedure.

A VTA/SRA self-appointed "expert" once listened as I played around with the VTA adjuster on my new tonearm. He was most careful to have the arm moved up and down two or three times before he finally announced where the sweet spot was. "Anyone can hear the effect," he proclaimed, but in fact I couldn't hear any difference whatsoever. A few hours after he left I found that the adjustment collar was not in fact threaded to the arm pillar, and that my "adjustments" had not altered arm height by even a mm.

Take what you will from this anecdote. I haven't bothered to try and enlighten the expert, and I've gently parried his offers to recheck the setting since then.